Liquid-cooled valve seat ring

ABSTRACT

The invention relates to a valve seat ring, which is easy to produce ( 2 ). The cooled valve seat ring comprises a cooling channel ( 4 ) which consists of a thin sheet of steel.

[0001] The invention relates to a cooled valve seat ring according tothe preamble of claim 1.

[0002] In the sector of outlet valves of internal combustion engines, anattempt is made to bring the cooling water mantle as close as possibleto the valve seat rings, in order to achieve a good removal of heat. Inthe current multi-valve cylinder heads of engines with direct dieselinjection and a centrally arranged injection nozzle, the tight spaceconditions often do not permit any satisfactory presentation of thecooling water mantle. The outlet valve ridge region, in particular, andthe ridge between the outlet channels and the injection nozzle must thenbe implemented in such a filigree manner that a water mantle core thatcan be used in series production can hardly be implemented. Therefore,valve seat rings having their own cooling channel were already proposed,whereby the cooling channel is configured to be either open or closedtowards the cylinder head.

[0003] Such valve seat rings are known from DE 3829339, DD 287078, or DE4328904. In this connection, a cooling channel that is closed towardsthe cylinder head is provided in the valve seat ring, in each instance,in the publications mentioned first. According to FIG. 5 of DE 3829339,the cooling channel consists of two solid components that are weldedtogether, into which the valve seat part is pressed. The cooled valveseat ring is cast into the cylinder head. The production of the cooledvalve seat ring from solid components is complicated and results in arelatively high weight disadvantage, and in internal stresses becausethe valve seat parts are pressed into the cooling channel part.

[0004] The invention therefore concerns itself with the problem ofcreating a cooling channel in valve seat rings of this type, which iseasy to produce and is light.

[0005] This problem is solved by means of a cooled valve seat ringaccording to Claim 1. Advantageous further developments are the objectof the dependent claims. In the solution according to the invention, thecooling channel, which consists of a thin sheet of steel, and is open onone side, is directly welded to the valve seat part.

[0006] Weight can clearly be saved with the sheet-metal cooling channelmade of a thin sheet of steel, as compared with the production fromsolid material. Preferably, the sheet-metal cooling channel is producedby means of bending, if necessary also by deep-drawing of a flat pieceof sheet metal. Another advantage of the sheet-metal cooling channels,as compared with the known cooled valve seat rings, consists in the factthat independent of the cross-section of the valve seat part, a freelyselectable channel cross-section can be set.

[0007] The thickness of the thin sheet of steel is preferably less than1.2 mm, and advantageously lies between 0.3 and 0.7 mm.

[0008] The invention will be explained in greater detail in thefollowing, using an exemplary embodiment. The drawing shows:

[0009]FIG. 1 a cylinder head having a cooled valve seat ring accordingto the invention,

[0010]FIG. 2 a valve seat ring having a centering collar.

[0011]FIGS. 3-5 various other variants.

[0012] A cooled valve seat ring 2, consisting of a valve seat part 3 anda sheet-metal cooling channel 4 welded onto the valve seat part, isconnected with a cylinder head 1 by means of a laminate casting process.

[0013] The ring space 5 formed by the sheet-metal cooling channel isconnected with a coolant circuit by way of bores 6 and 7.

[0014] The valve seat part 3 has a bevel that is characterized by a coneangle beta. The sheet-metal cooling channel 4 covers the valve seat part3 in the region of this bevel.

[0015] According to FIG. 2, the valve seat part 3 has centeringprojections 9 that fix the sheet-metal cooling channel 4 in place on thevalve seat part 3 during the welding process.

[0016]FIG. 3 shows a cut-out of a valve seat ring having a coolingchannel welded on, in cross-section, which is configured as apipe-shaped component having an open side that faces the seat ring,whereby the sheet-metal channel is joined to the valve seat ring withits two free shanks so as to form a gas-tight seal. The seat ring has abevel at an angle of alpha=45°, so that the free cross-sectional surfacefor the coolant flow is as great as possible. The bevel delimits thecoolant channel on the seat ring side.

[0017]FIG. 4 shows a similar valve seat ring having an angle alpha<45°,corresponding to a cone angle beta of<90°.

[0018] The cone angle formed by the bevel that runs around thecircumference of the valve seat ring, i.e. the cone angle beta, will liebetween 70° and 110°, in most cases.

[0019] The selection of the cone angle depends on the general geometricconditions, particularly on the minimum wall thickness values that mustbe maintained.

[0020] According to FIG. 5, the sheet-metal cooling channel isconfigured in closed, pipe shape, with a circular cross-section, and theseat ring has a recess adapted to the cooling channel diameter, intowhich the sheet-metal cooling channel is placed. In comparison with theexemplary embodiments presented above, at least one weld seam can beeliminated in this way.

[0021] It is advantageous if the welding process takes place in apartial vacuum, in order not to make the welding process for closing theseam more difficult due to escaping air.

1. Cooled valve seat ring (2) for a cylinder head (1) of an internalcombustion engine, having a valve seat part (3), characterized in thatthe cooled valve seat ring (2) has a sheet-metal cooling channel (4)consisting of a thin sheet of steel.
 2. Cooled valve seat ring accordingto claim 1, characterized in that the sheet-metal cooling channel iswelded onto or soldered onto the valve seat part (3).
 3. Cooled valveseat ring according to claim 2, characterized in that the sheet-metalcooling channel (4) is connected with the valve seat part (3) so as toform a gas-tight seal.
 4. Cooled valve seat ring according to claims1-3, characterized in that the cooled valve seat ring (2) is connectedwith the cylinder head material by means of casting technology. 5.Cooled valve seat ring (2) according to one of the preceding claims,characterized in that the cooled valve seat ring (2) has an alfin layerfor a connection with the cylinder head material.
 6. Cooled valve seatring (2) according to one of the preceding claims, characterized in thatthe valve seat part (3) is a sintered part infiltrated with copper, andthat the connection between the sheet-metal cooling channel (4) and thevalve seat part (3) is produced by means of infiltration of the valveseat part with copper, while simultaneously wetting the sheet-metalcooling channel.
 7. Cooled valve seat ring (2) according to one of thepreceding claims, characterized in that the sheet-metal cooling channel(4) is shaped in U shape and faces the valve seat part with its openside.
 8. Cooled valve seat ring (2) according to one of the precedingclaims, characterized in that the valve seat part (3) has projections(9), with which the sheet-metal cooling channel (4) is centered on thevalve seat part, so that no additional clamping devices are necessaryduring welding or soldering.
 9. Cooled valve seat ring (2) according toone of the preceding claims, characterized in that the valve seat part(3) is beveled on its surfaces that face towards the sheet-metal coolingchannel (4).
 10. Cooled valve seat ring according to claim 8,characterized in that the cone angle beta formed by the bevel on thevalve seat ring lies between 70° and 110°.
 11. Cooled valve seat ringaccording to claim 1, characterized in that the sheet-metal coolingchannel (4) is configured as a pipe-shaped or torus-shaped, closedcomponent, and that the valve seat part (3) has a recess that runsaround the circumference, is arc-shaped in cross-section, and is fittedto the sheet-metal cooling channel (4), into which the sheet-metalcooling channel (4) is placed.
 12. Cooled valve seat ring according toclaim 11, characterized in that the sheet-metal cooling channel (4) isconnected with the valve seat part (3) by means of a resistance pressingprocess or by means of soldering.
 13. Cooled valve seat ring accordingto claim 1, characterized in that the sheet-metal cooling channel (4) isarc-shaped in cross-section, with a segment angle of up to 300°, andthat the valve seat part is beveled on its surface that faces towardsthe circumferential opening of the sheet-metal cooling channel.